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old code was bad and wrong

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Lucia Ceionia 2023-07-16 20:54:12 -05:00
parent 5e07492252
commit 89349122f5
2 changed files with 16 additions and 105 deletions
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4
.gitignore vendored
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@ -1 +1,5 @@
/target
Cargo.lock
elf2le
a.exe
new.elf

117
src/dpmi_alloc.rs
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@ -2,81 +2,11 @@ use core::{ptr::null_mut, arch::asm, alloc::Layout};
use core::fmt::Write;
use heapless::String;
const PTR_COUNT: usize = 1024;
pub struct DpmiAlloc {}
impl DpmiAlloc { const fn new() -> Self { DpmiAlloc { } } }
struct Locked<A> {
inner: spin::Mutex<A>,
}
impl<A> Locked<A> {
pub const fn new(inner: A) -> Self {
Locked {
inner: spin::Mutex::new(inner)
}
}
pub fn lock(&self) -> spin::MutexGuard<A> {
self.inner.lock()
}
}
pub fn init_allocator() { unsafe {
ALLOCATOR.inner.force_unlock();
let mut t = ALLOCATOR.lock();
// 3.53 - DOS function 0FF91h - DOS/32 Advanced Allocate High Memory Block
// In: AX = 0FF91h
// EBX = size of memory block in bytes
// Out:
// if successful:
// CF clear
// EBX = linear address of allocated memory block
// ESI = handle of allocated memory block
// if failed:
// CF set
let ptr: u32;
let handle: u32;
asm!(
"mov edx, esi",
"int 0x21",
"mov eax, esi",
"mov esi, edx",
inout("eax") 0x0FF91 => handle,
inout("ebx") PTR_COUNT * core::mem::size_of::<DpmiPtr>() => ptr,
out("edx") _
);
t.ptrs = ptr;
t.global_handle = handle;
let mut ptrs = core::slice::from_raw_parts_mut::<DpmiPtr>(t.ptrs as *mut DpmiPtr, PTR_COUNT);
for p in ptrs.iter_mut() {
*p = DpmiPtr { ptr: 0, handle: 0 };
}
} }
#[derive(Copy, Clone)]
struct DpmiPtr {
ptr: u32,
handle: u32
}
pub struct DpmiAlloc {
ptrs: u32,
global_handle: u32
}
impl DpmiAlloc {
const fn new() -> Self { DpmiAlloc { ptrs: 0, global_handle: 0 } }
}
unsafe impl core::alloc::GlobalAlloc for Locked<DpmiAlloc> {
unsafe impl core::alloc::GlobalAlloc for DpmiAlloc {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
let mut dat = self.lock();
let mut ptrs = unsafe { core::slice::from_raw_parts_mut::<DpmiPtr>(dat.ptrs as *mut DpmiPtr, PTR_COUNT) };
let free_idx: usize = {
let mut tmp = None;
for (i, p) in ptrs.iter().enumerate() {
if p.ptr == 0 { tmp = Some(i); break; }
}
match tmp {
None => { asm!("int 0x1", in("eax") ptrs.as_ptr()); return null_mut(); }
Some(i) => i
}
};
// 3.53 - DOS function 0FF91h - DOS/32 Advanced Allocate High Memory Block
// In: AX = 0FF91h
// EBX = size of memory block in bytes
@ -88,32 +18,21 @@ unsafe impl core::alloc::GlobalAlloc for Locked<DpmiAlloc> {
// if failed:
// CF set
let ptr: u32;
let handle: u32;
let _handle: u32;
asm!(
"mov edx, esi",
"int 0x21",
"mov eax, esi",
"mov esi, edx",
inout("eax") 0x0FF91 => handle,
inout("eax") 0x0FF91 => _handle,
inout("ebx") layout.size() as u32 => ptr,
out("edx") _
);
ptrs[free_idx] = DpmiPtr { ptr, handle };
ptr as *mut u8
}
unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
if ptr as u32 == 0 { return; }
let mut dat = self.lock();
let mut ptrs = unsafe { core::slice::from_raw_parts_mut::<DpmiPtr>(dat.ptrs as *mut DpmiPtr, PTR_COUNT) };
let mut found_idx: Option<usize> = None;
for i in 0..ptrs.len() {
if ptrs[i].ptr == ptr as u32 { found_idx = Some(i); break; }
}
let handle = match found_idx {
None => return,
Some(i) => ptrs[i].handle
};
// 3.54 - DOS function 0FF92h - DOS/32 Advanced Free High Memory Block
// In: AX = 0FF92h
// ESI = handle of previously allocated memory block
@ -128,24 +47,13 @@ unsafe impl core::alloc::GlobalAlloc for Locked<DpmiAlloc> {
"int 0x21",
"mov esi, edx",
in("eax") 0x0FF92,
in("ebx") handle,
in("ebx") ptr as u32 - 0x10, // handle should be just 0x10 less than the pointer
out("edx") _
);
ptrs[found_idx.unwrap()] = DpmiPtr { ptr: 0, handle: 0 };
}
unsafe fn realloc(&self, ptr: *mut u8, _layout: Layout, new_size: usize) -> *mut u8 {
if ptr.is_null() { return null_mut(); }
let mut dat = self.lock();
let mut ptrs = core::slice::from_raw_parts_mut::<DpmiPtr>(dat.ptrs as *mut DpmiPtr, PTR_COUNT);
let mut found_idx: Option<usize> = None;
for i in 0..ptrs.len() {
if ptrs[i].ptr == ptr as u32 { found_idx = Some(i); break; }
}
let old_handle = match found_idx {
None => return null_mut(),
Some(i) => ptrs[i].handle
};
// 3.55 - DOS function 0FF93h - DOS/32 Advanced Resize High Memory Block
// In: AX = 0FF93h
// EBX = new size of memory block in bytes
@ -159,23 +67,22 @@ unsafe impl core::alloc::GlobalAlloc for Locked<DpmiAlloc> {
// if failed:
// CF set
let ptr: u32;
let handle: u32;
let new_ptr: u32;
let _handle: u32;
asm!(
"xchg edx, esi",
"int 0x21",
"xchg esi, edx",
inout("eax") 0x0FF93 => _,
inout("ebx") new_size as u32 => ptr,
inout("edx") old_handle => handle
inout("ebx") new_size as u32 => new_ptr,
inout("edx") ptr as u32 - 0x10 => _handle
);
ptrs[found_idx.unwrap()] = DpmiPtr { ptr, handle };
ptr as *mut u8
new_ptr as *mut u8
}
}
#[global_allocator]
static ALLOCATOR: Locked<DpmiAlloc> = Locked::new(DpmiAlloc::new());
static ALLOCATOR: DpmiAlloc = DpmiAlloc::new();
#[doc(hidden)]
pub fn _print(args: core::fmt::Arguments) {